The 72 to about 74 or 75 TQUAD are best. The 75, 76 truck quads are good also because lack of EPA junk, jets can be found for them or you can take stock ones and drill out. That said there are a few racers that swear the 71 and early 1000 quads are slightly better. I have 4 of the 71's and the ultra ultra rare jet and rod kit for them, but I haven't run one yet so can't say first hand. Big key is to make sure the center section is not warped and is square, and when seting up use the factory spec to start and do them in the order specified in the FSM. If anyone needs the jet drilled LMK
